The Usefulness of Measuring the Second Metacarpal Length as a Predictive Index for Growth Velocity during GnRH Agonist Treatment in Girls with Central Precocious Puberty

ABSTRACT

PURPOSE: The growth velocity in patients with central precocious puberty during treatment cannot be predicted. There is a positive correlation in growth among the long bones of the body and the length of the femur and tibia may determine individual height. We want to determine whether the second metacarpal bone can be used as a predictive index for growth velocity during gonadotropin-releasing hormone (GnRH) agonist treatment. METHODS: Thirty-four female children who were diagnosed with precocious puberty at our clinic and treated with GnRH agonist for about 1 year were included in this study. Patients who had growth-related disease, such as growth hormone deficiency and thyroid diseases were excluded. We reviewed their medical records retrospectively. We measured their height and the second metacarpal length from the X-ray film (left hand Anterior-Posterior at the time of their diagnosis and about a year after their GnRH agonist treatment. RESULTS: The age of the subjects was 8.5+/-0.6 years. The growth velocity during treatment was 4.9+/-1.2 cm/yr. There was a positive correlation between height and the second metacarpal length at diagnosis (P = 0.000, r = 0.666) and at one year after treatment (P = 0.000, r = 0.654). There was no correlation between the second metacarpal length at diagnosis and growth velocity during treatment for 1 year. CONCLUSION: We could not find the correlation between the second metacarpal length and growth velocity during GnRH agonist treatment for 1 year. However, the second metacarpal length showed a positive correlation with height before and after treatment. Therefore further study should be done to discovering the mechanisms working during GnRH agonist treatment including bone age, midparental height and so on.